Ad hoc meetings are frequent in a business environment. Ad hoc meetings are meetings that are scheduled at the spur of the moment and typically contain only a few participants. By way of example, assume a businessman telephones a businesswoman to have a telephonic meeting. During the meeting they both realize that they need to share some data or video. One way they could schedule this ad hoc meeting to exchange data or video is by using a scheduling application (such as Microsoft® Office Outlook®) schedule the meeting and e-mail the data or video. One problem with this method is that the data or video could be quite large and make take a long time to attach or send. Another way this ad hoc meeting could occur is by both parties agreeing to rendezvous at a certain network address on a network. It should be noted that this network could be a local area network or a wide area network (such as the Internet). Moreover, the term “network address” is used generically to refer to any computer network identifier such as an identifier for a computer or device on a TCP/IP protocol network (an IP address), a Session Initiation Protocol (SIP), or a Uniform Resource Identifier (which includes Uniform Resource Locator (URL) and Uniform Resource Name (URN). This method, however, is prone to error since network addresses are notoriously long and difficult to communicate audibly.
Another way to schedule ad hoc meetings is to use a distributed meeting (DM) technique. DM techniques provide multi-party conferencing and recording of meetings. By way of example, one way to schedule ad hoc meetings using this technique is by using multiple DM devices, such as cameras, microphones, and speakers. These techniques typically use an audible audio watermark. In general, an audible audio watermark includes using any conventional audio-based encoding method, such as DTMF or MFSK encoding. The advantage of using an audible watermark is that it can have a relatively short duration (as compared to an inaudible watermark) while transmitting the same amount of data. For example, a typical network address can be transmitted in an audible watermark having duration of a few hundred milliseconds, while an inaudible watermark would require several full seconds to transmit the same address. One disadvantage, however, with audible watermarks is that they can be altered by mixers and other audio processing equipment.
One such DM technique transmits an entire network address of a rendezvous point on the Internet using an audible or inaudible audio watermark. This gives each participant a location of where the data or video can be seen. This technique typically uses an audible watermark since the data transfer it much faster than an inaudible watermark. The inaudible audio watermark includes altering the frequency spectrum of an audio signal to embed a pattern. This pattern represents the data being encoded, which in this case is the network address. The inaudible watermark is low-amplitude noise that is inaudible to humans. The advantage of using an inaudible watermark is that it is not distracting to meeting participants as there is no audible noise to interrupt a participant's train of thought. However, as stated before a network address can be quite long, and when done with an inaudible watermark at a low-bit rate it would take quite long time to receive the entire network address (on the order of minutes at a low-bit rate). Thus, using inaudible watermarks to transmit a network address is impractical.
Another way to schedule ad hoc meetings is by using an Instant Messaging (IM) application. There are plug-ins that can be used for IM applications that can commence a DM session. The problem with this method is that all meeting participants must be running the IM application, and not everyone uses an IM application. In reality, the telephone network is much larger and has many times more users than use IM applications. Thus, methods that leverage the telephone network as a way to start an ad hoc meeting are more practical.